This invention is directed to optical couplers and more particularly to a method of coupling a single-mode optical fiber to a single-mode, optical, channel waveguide end-fire coupler for optical communication systems.
Heretofore optical waveguides and bundles of optical fibers have been used for transmission of light and coupling means has been provided to couple light into and from each of the above. The present state of the art makes use of single mode optical fibers both solid and tubular types. These have been developed such that the propagation losses have been reduced to a few decibles per kilometer. Also, the performance of integrated optic devices like modulators/switches have been improved. These single mode fiber systems require practical and efficient low-loss single-mode fiber-to-integrated optics couplers to improve the loss characteristics. One of the main drawbacks in single mode optical fiber couplers is the difficulty caused by the smallness of the light guide dimensions. It is well known that efficient couplers require an extremely accurate alignment and a rugged assembly to maintain the accurate alignment. U.S. Pat. No. 3,948,582 sets forth an optical fiber connection for coupling an optical fiber to an optical fiber and is designed to be disconnected and reconnected again with reasonable accuracy. There is a need in the optical fiber communication art to connect single mode optical channel waveguide with accurate alignment for the least loss in the coupler.